Causes of ice age intensification across the Mid-Pleistocene Transition ...

• Main Authors: Chalk, Thomas B., Hain, Mathis P., Foster, Gavin L., Rohling, Eelco J., Sexton, Philip F., Badger, Marcus P. S., Cherry, Soraya G., Hasenfratz, Adam P., Haug, Gerald H., Jaccard, Samuel, Martínez-García, Alfredo, Pälike, Heiko, Pancost, Richard D., Wilson, Paul A.
• Format: Text
• Language: English
• Published: National Academy of Sciences NAS 2017
• Subjects: 550 Earth sciences & geology; Ice Sheet; Southern Ocean
• Online Access: https://dx.doi.org/10.7892/boris.107874; https://boris.unibe.ch/107874/

Conflicting sets of hypotheses highlight either the role of ice sheets or atmospheric carbon dioxide (CO2) in causing the increase in duration and severity of ice age cycles ∼1 Mya during the Mid-Pleistocene Transition (MPT). We document early MPT CO2 cycles that were smaller than during recent ice age cycles. Using model simulations, we attribute this to post-MPT increase in glacial-stage dustiness and its effect on Southern Ocean productivity. Detailed analysis reveals the importance of CO2 climate forcing as a powerful positive feedback that magnified MPT climate change originally triggered by a change in ice sheet dynamics. These findings offer insights into the close coupling of climate, oceans, and ice sheets within the Earth System. ...